Many voice disorders are related to abnormalities of the vocal fold lamina propria. The major proportion of lamina propria is extracellular. The extracellular tissue is composed of fibrous proteins (collagens and elastins) and interstitial or "filler" proteins (proteoglycans and structural glycoproteins). Each of these proteins has a specific biologic function in phonation. Some benign laryngeal diseases represent a disorder of the extracellular matrix, meaning that the normal composition and ratio of filler to fibrous proteins is altered. This proposal will investigate the exact composition of the normal vocal fold lamina propria as it relates to age, gender, and race. Furthermore, this composition of normal folds will be compared to the abnormal conditions found in surgically removed benign laryngeal diseases. To determine the effect certain molecular variations in lamina propria composition have, hemilaryngeal vibration and viscoelastic measurements will be made to obtain biomechanical information; the results will be matched to the molecular analysis of the paired vocal fold. This will allow a comparison of biomechanical performance based on the molecular composition of the lamina propria. To obtain precise quantitative histologic information we will use a highly refined image analysis system developed for comparisons of location and extent of protein deposition in tissue. Lastly, this information will be used to model a therapeutic approach for some vocal fold diseases. Computer and tissue modeling (project RI) will employ the histologic and biomechanical data to arrive at best solutions for select problems and possible treatment.